Pests, weeds and diseases cause a yearly loss of around 30% of the world's agricultural production. Fungal diseases have been one of the principal causes of crop losses ever since humans started to cultivate plants. To date, the epidemic spread of fungal diseases is controlled by i) various crop husbandry techniques, such as crop rotation and avoiding the spread of infested soil and pathogen-carrying plant materials, ii) breeding of fungus-resistant cultivars of crops, and iii) the application of agrochemicals. Although breeders have succeeded in producing cultivars resistant to fungal diseases, the time-consuming processes of making crosses and back-crosses and the selection of progenies for the presence of resistance traits make it difficult to react adequately to the evolution of new virulent fungal races. Therefore, farmers often have to use chemicals. Agrochemicals are costly, and eventually they become less efficient due to the evolution of the pathogen. In addition, both their production and their persistence in the soil after use are potentially harmful to the environment. The growing concern about the environment, together with a strong motivation to lower production costs, encourages the development of crops that require fewer chemicals. To protect themselves against pathogens, plants produce various antimicrobial compounds, either secondary metabolites or proteins, whose production can be either constitutive or inducible upon pathogen perception. Successful pathogens have found effective ways to avoid or resist contact with these antimicrobial compounds. Taking into consideration that these compounds and the ways they are produced strongly differ from plant to plant, it is not surprising that most pathogens are highly specialized and have a very narrow host range, often limited to one species or even to certain genotypes within that species. During the last decade, several research groups have discovered plant genes (antifungal genes), which directly or indirectly limit the growth of fungal pathogens. In several documented cases, it is found that overexpression of such antifungal genes in plants confers resistance to one or more fungal pathogens. There is, however, a need for the identification of novel antifungal peptides, which can be used to combat fungi by generating either transgenic plants or applying these antifungal peptides directly to plants.